1. Field of the Invention
The present invention relates to an apparatus and method for reproducing a recording medium, and particularly to an apparatus and a method for reproducing a recording medium that make it possible to control reproduction by a simple operation by recording flags for controlling reproduction of AV data onto a disk and using the flags at the time of reproduction.
2. Background Art
Optical disks are disk type recording media which are recordable and removable from a recording and reproducing apparatus. Such recordable optical disks can be large-capacity media having a capacity of a few gigabytes or more and can be used as media for recording AV (Audio Visual) signals such as video signals and the like.
A source (source of supply) of digital AV signals, which can be recorded on the recordable optical disks, can include digital satellite broadcasting such as CS (Communication Satellite) digital broadcasting and BS (Broadcasting Satellite) digital broadcasting in Japan, for example. In addition, digital terrestrial television broadcasting and the like are being considered for the future.
Digital video signals supplied from these sources are typically video-compressed by an MPEG (Moving Picture Experts Group)-2 Video system. Also, in a recording apparatus, a recording rate specific to the apparatus is generally determined. When a digital video signal from a digital broadcast is recorded on conventional video storage media for consumer use, in an analog recording system, the digital video signal is decoded, subjected to digital-to-analog conversion and band limitation, and recorded. In a digital recording system such as an MPEG-1 Video system, an MPEG-2 Video system, a DV (Digital Video) system or the like, on the other hand, the digital video signal is decoded by a tuner, then re-encoded using an encoding system and a recording rate specific to the recording apparatus, and recorded.
However, such recording methods may involve degradation in picture quality because the supplied bit stream is decoded, thereafter subjected to band limitation or re-encoding, and then recorded. When a video-compressed digital signal is recorded and a transmission rate of the video-compressed digital signal exceeds a recording rate of the disk, the recording and reproducing apparatus needs to decode the digital signal, thereafter re-encode the digital signal so as to decrease the transmission rate to an upper limit of the recording rate of the disk or lower, and then record the digital signal. However, when the transmission rate of the input digital signal does not exceed the recording rate of the recording and reproducing apparatus, degradation in picture quality is minimized by a method of recording the supplied bit stream, as is, without decoding or re-encoding the bit stream.
The transmission rate of digital signals may not always be constant. When a digital signal is transmitted by a variable rate system in which the bit rate of the digital signal fluctuates with time, a tape recording system having a fixed recording rate, because of a fixed rotational speed of a rotary head, maintains a constant bit rate at all times by stuffing empty packets, for example. This means recording at a maximum bit rate at all times and hence wasteful consumption of recording capacity. On the other hand, a disk recording apparatus can temporarily store data in a buffer, and record the data onto a disk on a burst and an intermittent basis. Hence, such disk recording apparatus may eliminate the need for inserting empty packets, and can therefore use capacity on a recording medium in a less wastefull manner.
Thus, a recording and reproducing apparatus that records a digital broadcast signal, as is, without decoding or re-encoding the digital broadcast signal as in a data streamer and uses a disk as a recording medium, may be more desirable in the future when digital broadcasting becomes more mainstream.
In the present application, a unit in which a user selects and reproduces AV data (i.e., a unit in which the user expects reproduction to be performed continuously) is referred to as a playlist. An example of a playlist is continuous video (contents) from a start of recording to an end of the recording.
A function of preventing an entire disk or playlists recorded on the disk from being readily reproduced is considered. A mechanism that sets a code number and does not allow reproduction unless the code number is input may be useful when there are contents not desired to be viewed by others and when there is a playlist not desired to be changed.